Seems this is a bigger issue for some USB-3.0 Hubs. With the recent changes in 5.8 development cycle the renesas_usb_fw.mem is now needed for some rensas controller like uPD720201 and uPD720202. However this firmware is due to its license not distributable.
There are some commits:
If we look closer we got this note:
tristate "Support for additional Renesas xHCI controller with firwmare"
depends on USB_XHCI_PCI
Say 'Y' to enable the support for the Renesas xHCI controller with
firwmare. Make sure you have the firwmare for the device and
installed on your system for this device to work.
If unsure, say 'N'.
So we will try to remove that driver support as recommended by upstream and revisit it, as soon as the firmware lands into linux-firmware.
The firmware image can be extracted from the Windows driver.
A viable source is the "PP2U-E" (USB3.0 Host to PCIe Adapter)'s
"Firmware download (ver 220.127.116.11) Jun 15, 2012" file. It contains
the K2013080.mem file which needs to be placed in /lib/firmware.
So it seems after all it is the following commit which breaks the support of some USB 3.0 controllers:
It more or less forces the driver to look for the firmware as needed. So by deactivating the xhci-pci-rensas driver you still get the notification that you might miss some firmware. So it is hard to fix this.